1. Field of the Invention
The present invention relates to the throttle body structure having an idle air control valve and a plurality of bypass passages.
2. Description of Related Art
A multi-cylinder throttle body on which a housing of an idle air control valve is integrally formed is known (see JP-A-2007-132235, for example). JP-A-2007-132235 discloses the throttle body structure that includes an insertion hole for an idle air control valve and an approximately Y-shaped bypass passage formed on a plane orthogonal to the insertion hole between throttle bores formed in the throttle body in parallel to each other. The approximately Y-shaped bypass passage communicates with a bypass port that supplies idle air to a pair of throttle bores arranged adjacent to the idle air control valve and other throttle bores that are spaced apart from the idle air control valve. Air in the bypass port is supplied to the above-mentioned other throttle bores through hoses.
The above-mentioned prior art fails to disclose the arrangement of parts around the throttle body. When an injector is provided as a part arranged around the throttle body, for example, a fuel delivery pipe, a fuel supply hose and the like, which are connected to the injector, are arranged upstream of the throttle bore. Accordingly, in providing the bypass port upstream of the throttle body and by arranging hoses or the like, which are connected to other throttle bores spaced apart from the bypass port as in the case of the above-mentioned prior art, there exists a drawback that these parts are jammed with respect to an arrangement space so that the degree of freedom of arrangement of the parts such as the hoses, the injector, the fuel delivery pipe and fuel hoses is lowered.